In an interview with the Beijing Times, Wang Meng-shu, a railway expert at the Chinese Academy of Engineering, said that China is "considering" a high-speed rail plan that would run an estimated 13,000 kilometers -- about 8,000 miles -- (the Trans-Siberian Railway is around 9,000 km or roughly 5,500 miles) from northeastern China to Russia and then cross the Bering Strait through an undersea tunnel to reach Alaska.

The tunnel alone would be an impressive engineering feat. Around 200 km (125 miles) of undersea tunnel would be needed. That's about four-times longer than the current world's longest rail tunnel, the Seikan Tunnel in Japan.

Using high-speed trains that could reach speeds of 350 km/hour, the train would run from beginning to end in roughly two days, according to Meng-shu.

The China-Russia-U.S. line is one of four major high-speed rail projects Meng-shu discussed with the Beijing Times. Among them a Eurasian rail line connecting China to London and a Pan-Asian rail line starting in Kunming and connecting Vietnam, Cambodia, Thailand, Malaysia, and Singapore.

Of course, there are plenty of potential issues that all the lines will run into:

Cost

Intergovernmental cooperation

Engineering challenges

And the costs of the China-Russia-U.S. line alone might be enough to be skeptical that this project will ever become reality. When Quartz extrapolated the costs of similar projects to estimate the price tag of the China-Russia-U.S. line, it found that the final costs could exceed $200 billion. The tunnel alone could cost more than $50 billion. According to Quartz, this one line would be more than half of China's current ($300 billion) high-speed rail budget.

But obvious challenges haven't stopped China from continuing to pursue ambitious high-speed rail projects in the past. In fact, the China-Russia-U.S. line might not even be the most unbelievable high-speed rail news out of China recently. Researchers at China's Southwest Jiaotong University unveiled a super-maglev prototype using a vacuum tube that could one day allow high-speed train to reach 1,800 miles per hour. Speaking of expensive...